This is a prospective open-label, multicenter, long term continuation trial in which LJP 394 will be tested to evaluate the long-term safety and efficacy in patients with a prior history of active lupus renal disease. Both the safety and efficacy profile of LJP 394 will be assessed during the 48 week trial. All patients begin the trial with an 8 week "off treatment" period. This is followed by a 12 week "on treatment" period consisting of weekly intravenous administration of LPJ 394. This 20 week cycle repeats 2.5 times for a total duration of 48 weeks.